Cavitation refers to the formation of air bubbles in fluid in low-pressure condition which is lower than the saturation pressure.
It is a potentially damaging condition in which the fluid in pipes or sewers is at high velocities.
By Bernoulli?s Equation, at high flow velocities, the pressure head of fluid is reduced accordingly.
As the fluid pressure is less than saturation pressure, dissolved gases are released from the fluid and these air bubbles will suddenly collapse when the flow enters into a region of higher pressure.
This produces a high dynamic pressure which causes damage to the pipelines due to its high frequency.